The basal ganglia contribute to cognitive abilities such as skilled motor performance, executive function, and feedback-driven learning. While the maturation of intrinsic brain networks supporting these functions has been investigated, potential sex differences in the development of these abilities are not well-characterized. Here, we tested whether sex was associated with age-related differences in striatal intrinsic functional connectivity, cognitive abilities, and their association. Our sample included 110 healthy adolescents aged 9-14 years old from the Developmental Chronnecto-Genomics project (Dev-CoG). Cognitive abilities were assessed using several NIH Toolbox tasks (e.g., flanker, dimensional card sort, pattern comparison, and working memory). Resting-state fMRI (rs-fMRI) data were collected using identical multiband sequences (voxel size: 3.3×3.3×3.0 mm; TR: 460 ms; TE: 29 ms; 650 measurements) under eyes-open eyes-closed conditions (5 min. each). All fMRI data were aligned to the structural volume and transformed into Haskins Pediatric Atlas space. The relationship between behavioral performance and whole brain resting-state functional connectivity (RSFC) was examined as a function of sex using anatomically-derived striatal seeds for the caudate and putamen with covariates for variables such as age and task performance. We observed significant covariation between striatal RSFC, age, and performance. Further, our results indicated a significant difference in these relationships as a function of sex with increased age. These findings suggest that specific cognitive abilities are related to changes in striatal RSFC with other brain regions during adolescence, and that maturation of the networks serving executive functions and cognitive flexibility is significantly influenced by sex during development.